/Engine/Source/Runtime/Online/HTTP/Public/GenericPlatform/GenericPlatformHttp.h
Extract the URL-Decoded value of the specified ParameterName from Url. An unset return means the parameter was not present in Url, while an empty value means it was present, but had no value.
If ParameterName was found, the string value of its value (in URL Decoded format), otherwise the return value is unset
static [TOptional](API\Runtime\Core\IO\TOptional)< [FString](API\Runtime\Core\Containers\FString) > GetUrlParameter ( const FStringView Url, const FStringView ParameterName )